DeOssie, 36, played 13 seasons, made two Pro Bowls and won a pair of Super Bowls. He was a team captain in each of the past nine seasons.
"I am retiring from football," DeOssie said in a statement to ESPN. "As many of you know, I made this decision months ago, but I wanted to make a formal announcement to acknowledge those who have made this experience so awesome -- and this milestone so bittersweet."
DeOssie's contract expired at the end of last season. Former coach Pat Shurmur referred to DeOssie as a "big-time Giant" last year, after his final season ended when he was placed on injured reserve with a torn meniscus in his knee and a wrist injury.
The fourth-round draft choice out of Brown University was one of just 13 players from the 2007 draft still on an NFL roster last season.
DeOssie played in 199 regular-season games for the Giants, the fifth-highest total in franchise history. He made the Pro Bowl in 2008 and '10 and won rings in Super Bowls XLII and XLVI.
Steve and Zak DeOssie are the only father-son tandem to win the Super Bowl with the same franchise. Steve DeOssie was a linebacker and long-snapper with the Giants, Cowboys, Jets and Patriots. He played in 175 games in 12 NFL seasons, which included four and a half (1989-93) with the Giants, and started at linebacker in a Super Bowl XXV victory over the Buffalo Bills.
"Thank you for all that you have done and continue to do to make this journey, and especially this moment, mean so much," Zak DeOssie said to his dad in his statement. "You have been the best mentor, advocate, and friend through it all. Three rings for the DeOssies (so far) -- but we have so much more than that to celebrate together, in the past and going forward."
After being drafted by the Giants, Zak DeOssie made an immediate impact on special teams. He played in all 20 games (regular season and playoffs) during his rookie season and led the team with six special teams tackles during the first of two Super Bowl runs.
DeOssie didn't miss a game until his ninth professional season. He played in all 16 games in 11 of 13 years with the Giants and has been a staunch advocate for players' rights as an active member of the NFLPA executive committee in recent years.
DeOssie has already moved on to the next stage of his life, joining Goldman Sachs in private wealth management.
"Head down, hands steady, produce results," DeOssie said. "I learned from my time with the Giants that hard work pays off. As I walk away from the game as a player, I thankfully get to keep that mentality."